HIV-1 replication is dependent upon cellular co-factors to mediate its infectious cycle. Because of this, a small molecule that disrupts an essential interaction between an HIV-1 protein and its cellular co-factor can act as an anti-HIV drug. The identification of cellular co-factors is therefore a necessary first step in the development of novel anti-HIV drugs. This grant application proposes to identify novel HIV-1 co-factors in a set of 54 genes that our laboratory identified in a transcriptional profiling study. These genes are up-regulated in both activated CD4+ T cells and differentiated macrophages, and their up-regulation is dependent upon the Cyclin T1 protein. Cyclin T1 is a direct target of the HIV-1 Tat protein and it mediates RNAP II transcription of the integrated provirus. Although most of the encoded proteins in our gene list have not been evaluated for a role in HIV-1 infection, 10 (of 54) have been reported in the literature as having a role in the HIV-1 infectious cycle. In randomly generated sets of 54 genes that are expressed in both CD4+ T cells and macrophages, we observed that only 2 or 3 genes (average 2.4) have links to HIV-1. Thus, our set of 54 genes is over-represented in proteins involved in HIV-1 replication (p value of <0.00021). This statistical analysis argues that our list is highly likely to contain novel viral co-factors. To identify novel HIV-1 co-factors, we propose two Specific Aims. Preliminary experiments with one gene from our list, Casein kinase 1 gamma 1 (CSNK1G1), suggests that this cellular protein is a co-factor that affects HIV-1 virion infectivity. Specific Aim #1 proposes to investigate the role of CSNK1G1 in HIV-1 replication and determine if the cellular factor affects virion infectivity. Specific Aim #2 proposes to conduct a shRNA screen to determine which of our set of 54 Cyclin T1-dependent genes have a role HIV-1 replication. Completion of the proposed research is likely to identify new targets that can be the basis for the development of novel anti- HIV therapeutics. Given the ability of HIV-1 to acquire resistance to current anti-viral drugs and the toxicities of these drugs for many patients, an ongoing challenge for basic research is the development of novel anti-HIV drugs. PUBLIC HEALTH RELEVANCE: Cellular co-factors that are necessary for HIV-1 protein can be the basis of anti-HIV drugs. We have identified a set of 54 cellular genes that are likely to contain new HIV-1 co-factors. The research proposed in this application will investigate if this gene set does indeed contain novel HIV-1 co-factors that can be targets for anti-HIV drugs.